Screw-cutting die and holder therefor.



No. 871,451. PATBNTED, Nov. 19, 19o?.

` A.- J. SMART. A

SCREW CUTTING D11; AND VHOLDER THBRBTOR.

APPLICATION FILED OC'JLSO,l 1906.

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INVENTOR Jnfmafr.

ATTO/UVEK? PATENTBD NOV. 19, 1007,

J. S IART.

SCREW CUTTING DIE AND HOLDER THEREFOR.

APPLICATION FILED OCT. 30, 1906.

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f'ametersbetween certain limits.

ALBRT J. SMART, OF GREENFIELD, MASSHUSETTS.

sonnw-ouarfme nm AND HOLDER THEREFOR.

To all whom 'it may concern:

Be it known that 1ALBER1 J. SMART, residing at Greem'ield, in the countyof Franlglin 'and State of Massachusett's, have invent- Ved certain new and useful Improvements in .Screw-Cutting Dies and Holders Therefor, of

`whichthe following is a specification.

My invention relates to certain new and useful improvements in screw cutting dies and 'stocks or holders therefor.

Primarily, my invention has for its object to'provirle an elastic, reversible and adjustf,

able dieofy'a very simple and eiiective constructiompnfhich will be inexpensive to man- 15 ufacturaiasy to adjust, easy to center and havmga '-i'gapacity to cut either larger or' smaller th its normal size.

` prises@ My invent on also has for itsobject to pro- -vide a stock orholder for the die to cooperate therewith. f .j

In its generic nature, my invention comdie ,consisting of a tubular member provided with a peculiar construction., thengers or prongs of the. die having longitudinal grooves to copvscrews of the stoo also lprovided with conical end portions `to` cooperate with conical seats in the hoider so that. the screw cutting portions of the die all of which will be iirst or holder. The die isv maybe drawn closer together` o1` allowed to spring farther apart as 1t 1s made necessar to cut threads on bars or rods of varying d1- In its more subordinatenature, my invention.` comprises certain novel construction, combinatlon and detail arrangement of arts, described in etail, and then be specifically pointed out in the appended claims, reference being had to the accompanying drawings, in which Figure'l, is a .perspective viewpf a die stock and die embodying my invention.

Fig. 2,is a central longitudinal section thereof, showing the position of the parts when the die is adjusted in its first position with. its cutting )ortion adjacent the guide of the stock.`

Fig. 4, 1s a view similar to Fig.` 2,` showing the die adjusted to cut threads on a rod of lesser diameter than those under the adjustment shown in Fig. 2. Fig, 5, is a view similar to Fig. 2, showing a Specification of Letters Patent.

Application filed October 30, 1906. Serial Ilo. 341.285,

- shown in Fig.

plurality of prongs or fingers i which 'carry .the cutting teeth and are more `or less of aresilient nature, by reason of theiry Y ig. i3, is a similar view showing thel f die reversed.

Patented Nov. 19, 1907.

modified form of die stock. Fig. 6, is a perspective View of a machine collet. Fig. 7, is a lcentral vertical longitudinal section of a ma'c'hine collet. Fig. 8, is a detail perspective -view of one of the dies removed from its holden Fig. 9, is a side elevation of the die slightly modified form of die stock.

eferring nciw to the accompanying drawings in which like letters and numerals of reference indicate like parts in all of the figures, it will' be seen that my improved die 1 comprises a body portion 1a which is cut away as at 1b to form pron s l, preferably three in number, and space e ui-distantly apart, the die having a centrfil prongs lcbeing provided' on their inner faces with cutting projections 1d, as indicated. The prongs Flare provided with longitudinal grooves 1h lying m parallel alinement with yhe central axis of the 'die and the die 1, has

l"its outer surface provided with beveled or conical faces 1"--1g for a purpose presently feXplaned.

In the process of manufacturing dies of this type the die is made to cut larger than its'normalsize by a process of hardening and tempering. In iact, it is always larger than its normal size as the process expandsv or preads the prongs of the cutting end ofthe ie and hence after the'die has been formed the prongs or cutting ends of the die are slightly expanded, as indicated in Fig. 2. Of course, m practice, this expansion of the cutting ends of the prongs of the die will be only slight and will de end upon the size of the die, and hence it becomes necessary to provide means whereby the cutting ends of the prongs of the die can be drawn together to out threads on a blank. of Va given size known as the normal size blank which the die is adapted to cut. My die also has its cutting pro ections so arranged that the die can be used to cut either from the face side or from the butt or bottom side of the same, as will be presently more f'ully explained.

I am aware that prior to my invention dies formed with prongs and having their outer surfaces smooth have been in use and means haveA been provided for drawing the prongs or cutting ends of the diel together, and this means so far as. I am aware has usually been in the nature of a clamp band, such for instance as th at disclosed in a patent granted to W. L. Dixon, granted May 5,

S. Fig. 10, is adetail view of a bore le and thel 1391; #451,390 A serious obiection to this method oi adjusting theonds of the die is vthat this method of adjusting the prongs is very imperfect since the edges are not drawn equally to the center or axial line oi the die;

the cutting edges nearest the screws wili be irst eiieeted, thereby making an unequal adjustment of said cutting edges. To obvate this undesirable feature, have provided an improved Aforni of holder ior this particular die which has provisions for unie forinly adjusting the die. v

By reference to Figs. to 5 inclusive it will be seen that the die' stock comprises a body 2 having laterally projected hub portions .2 into which the handle members 3,

are screwed. The handle member 3 may be in the 4n'anore of tubuly ends 3 and -milled han f ngaging portions 3b, as indicated ini-,Fig yThe body portion 2 of the stock ont to vforno a cylindrical chamber i'ich merges with a shoulder 2 aten; and is irovided with threaded portiini12d?v arranged aperture4|-`v 9.5 whose surface is the frustum of -aoone h'aying its greater diamsm ter adjacentthe chamber 2b.

Projecting from the hotly portion 2 adjacent the web ZZ" is a guide 2f which is rontrally apertured at 2g to porniit passage of the blank to be operated upon, the guide 2f being spaced 'from the body portion 2 by lugs 2h, as shown, to form an opening 2k be'- tween the guide 2f and the wel) 2" to perzpit the discharge of chips, ctc. AKscrew cap having a iniiled edgew 4*? and aithreaded barrel 4l is provided. to cooperate with the threads Zd and close the chamber "l". The milled edge 4 inajwhe provided with radial sockets 4" to receive an` operating tool or wrench, if desired. vThe capv 4 is provided with a rentralaprrture wl'iose surface is in the nature of a irustnni of a @one whose edge of greater diameter is at the threaded ond of tho barre-l 4* so that the greater diameters of the conical frost-nm urtare-sof the apertures and l will lio adjarvnt onl another. i

"he hody portion 'l of thai stonk is provided with a serios ol" srt soroiif's 5 preferably arranged triangularly to cooperate withthv grooves 1h oi' thrdic and strengthen or rein- .force the cutting prongs thcneof as well as hold the dit` in position in thi` stock from turning.

ln the pren-,tical implication of' my invention the div l is inserted into tln` hody portion 3 oi' the stock with its iatttingrnd down 'adjacent the guidi` 2" so lhahthv surface l" oll iw cutting' rnd of 'the di(` l Will coincido with that of th(l aportur 2" and th(` ioliical snrl'iu'o l ol' tho die l njfdlsooincidc with that ol'tho apex-tori` l ol'w tht/i rap i. 'i

Whoo lhopnrts are' inftho position shown 9 ods having closed.

` n at the' ot ier end.. The shoulder 2c is provided with a centrally,

in Fig. 2, before the aap 4 is screwed tightly in the chamber or socket n the Yprong-s i of the4 die will he in their expanded position and when the die and stockV are in the position shown. in Fig. 2, the threads will cut larger than tneir normal size, and when it is desired to out a thread of. the normal size d the die then the cap i can be sorerred down as shown in Fig. 4, it being understood that' hy virtue of the conical ends of the die and the conical'suriaoe 2e thefprongs of the die will be drawn .together equally toward the center or axial line of the die and hence the cutting prongs of the die will always remain centered so that they will properly'oporate upon the blank. l it is .often desirable in practice, toont a thread, say for instance, on a bolt, all the Way down to thehead of the bolt. When this is to be donethe thread can be started `with the die l in the' stock in the position shown in Figs; 2 or. It, as the oase may be,'until the thread has been cut as far as may he desired, or until the head or" the bolt abuts the guide 2", after which the bolt can be Withdrawn from the die or stock by unsorewing the cap 4, and inverted say in the position shown in Fig. 3, aiterivhich the thread may be continf ued on the bolt untii thc head engages thc cutting end 1X of thi"l prongs i", tous running thel thread all the Way down to the head of the holt; `When the die is' in the position shown in Fig. 3, the adjustment of thefmip Il in its socket will either' draw tl'ie-prongsofthe die 19o together or Wrinit them to spring 'apart de",

pending upon tho distance in Winch the capis screwed in its socket and when thel die is inl l the position shown in Fig. 3 the adjustment of the prongs toward or from each other is 105 eil'ectcd by the conical'surfaoe if of the die and that of the aperture il, Thus it will he seen .l have proide'da very simple and eil'ectivo construction of diestocir' e capable of use in connection with my iin-f 110 proved die and oi sur-rh a characte'rthat the i dif,l van be instantljY centered in the stockby reason of the conirai ends of the dieand the 'conical surface ol the apertures 'and position in the stock, tho' sot screws 5 can he adiustod to snugly iit in thegrooves l, aftei which no further adjustment-of the screws 5 is necessary, since when itis desired-to remove the die from tlustm-.lr or ohangeits'adi2() instnunt, it is only necessary to withdraw the die say from thc` iosition shown in` Fig. 2

and after inverting tln same slide it bach in' place iii 'ihr stock. The grooves running from inserted without moving the 'set sercws.

Again, my improved construction of die is 'equally woll adapted for nso in a hand stock, as shown in Figs l to 5 inclusive or the` same may he used in a machine collet as showrn .3.30

and after thc die has onen placed in its initiati 15 i end yto ond o ihr die, permit the suine to be 7. A die holder com rising a body portion having an internally t eaded chamber and a central passage provided with a conical seat, a screw cap for said body portion having a threaded hub to project into the chamber ofthe body portion and having a central aperture provided With a conical seat, an adjustable and reversible resilient die having a section engaging the aforesaid conical seats,

and means carried by'the body portion andv coperatively engaging the die 1n all of its operative positions for reinforcing the same and preventing the rotation thereof and a Work guide at one side faceA of the holder, substantially as shown and described.

8, As a new article ofmanulacture, a resilient die having prongs and conical outer endv surfaces and lon it-udinal grooves on its outer surfaces exten mg from end to end ci the die, substantially as shown and described.

, 9. As a new' article of'manufacture, a resilient die having ciltting pron s and longitudinal grooves on its outer su aces extending from end to end thereof, substantially as shown and described. i 

